1. Technology Field
The present invention relates to a data writing method. More particularly, the present invention relates to a data writing method for a flash memory, and a flash storage system and a controller using the same.
2. Description of Related Art
With a quick developing of digital camera, cell phone camera and MP3, demand of storage media by customers is increased greatly. Since a flash memory has the advantages of non-volatile, energy saving, small size and none mechanical structure etc., it is suitable for portable applications, and especially for portable battery-powered products. A memory card is a storage device applying an NAND flash memory as the storage media. Since the memory card has a small size and a large volume, and is easy to be carried, it has been widely used for storing important personal data. Therefore, the flash drive industry becomes a hot industry within the electronics industry recently.
Generally, in the flash memory, a programming unit (for example, a page) is less than an erasing unit (for example, a block). Therefore, when update data is written into the flash memory, moving of valid data therein is required to be performed. With progress of fabrication process of the flash memory, and to satisfy a large volume of the storage media, design capacities of each programming unit and erasing unit become greater, which may lead to a fact that more time is required to move valid data in the erasing unit. However, for a flash memory having a large erasing unit, response time for a data writing command may exceed that of some latest flash storage systems (for example a solid state drive (SSD)) due to excessive block moving time, and therefore the flash memory having the large erasing unit cannot be used. Accordingly, the response time for each data writing command of the flash storage system is required to be shortened.